Electrical gas-lamp and method of producing light by means of the same.



F. SKAUPY.

ELECTRICAL GAS LAMP AND METHOD OF PRODUCING LIGHT BY MEANS OF THE SAME. APPLTCATION FILED MAR. 12. 1913.

1 a 1 5 1 7 1 29 Patented Aug. 24, 1915.

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DB {T L a. W- W- ATTGR/VEVS FRANZ SKAUPY, OF BERLIN, GERMANY, ASSIGNOBI' T0 DEUTSCHE GASGL'U'HLICHT AKTIENGESELLSCHAF'I' (AUEBGESELLSCHAFT),

POMTIOIV OF GERMANY.

ELECTRICAL GAS-LAMP AND METHOD OI IRODUCING LIGHT BY MEANS OF THE SAME.

Application filed March 12, 1913. Serial No. 758,692.

To all whom it may concern:

Be it known that I, FRANZ SKAUPY, a subject of the Emperor of Austria-Hungary, and resident of Berlin, Germany, have invented a new and useful Improvement in Electrical Gas-Lamps and Methods of Producing Light by Means of the Same, of which the following is a specification.

My invention relates to lamps imwhich illumination is produced by the action of electrical currents upon a rare gas or gases.

The object of the invention concerns an electric gas lamp in which rare gases are caused to produce illumination by the action of electrical currents and this not by means of known glow light phenomena but through phenomena of an arc light character such as are found in the known mercury vapor lamps.

In order that the production of light may take place economically, there is provided a cathode of Very electro-positive metal, preferably an alkali metal, which entails in the art of electrical discharges here under consideration, only a very small potential loss and therefore a very small economic loss.

Such metals are e. g. sodium, lithium, potassium and the like.

The essence of the invention consists in that the production of light takes place exclusively or almost exclusively, through the illuminating property of the rare gases for which purposes the current emerges from the gases through a cathode of very electropositive metal as aforesaid, so disposed that its vapors or particles do not substantially share 1n the production of light.

In order to make clearin what respects the invention difi'ers from the known rare gas lamps on the one hand and the known alkali vapor lamps on the other hand, there .will now be set forth the processes which take place in the known lamps-and also the processes which take place in this new lamp.

In the known alkali vapor lamps the alkali metal vaporizes and its vapors, through the action of an electrical current, produce light. The illuminating body in this lamp is, therefore, glowing alkali vapor metal. In the known rare gas lamp the rare gas illuminates through the influence of the electrical current. The exit of the current from the rare gas to the cathode takes place, however, only with an extraordinarily high potential fall,

Specification of Letters Patent.

which principally showed mercury vapor OF BERLIN, GERMANY, A COB- Patented Aug. a4, 1915.

electric circuits of to 120 volts. This has led to the production of lamps which are operated at a very high voltage, since the usual voltages up to 220 volts are co letely absorbed or taken up by the loss at t e cathode. In place of solid electrodes, mercury electrodes have also been employed. In such cases, however, the mercury necessarily vaporlzed in such quantities that the illumination of the tubes was dependent essentially upon the presence of the mercury vapor. One did not, therefore, obtain a light which necessarily contained the lines of the rare gas spectrum but a light the spectrum of lines. It has also been proposed to cool the mercury, through special external or other arrangements, so thoroughly that the temperature of the mercury vapor will be greatly lowered and therefore the light due to the mercury vapor correspondingly reduced. To this end, however, it would be necessary to employ artificial cooling means which would have to be reduced to a temperature very much below that of the space to be illuminated. This is impracticable for a commercial lamp.

According to the present invention essentially only the rare gas produces light; the spectral lines of the alkali vapor do not take part substantially in the production of light and the spectrum shows either only very weak lines or no lines at all of alkali metal, and the production of light is conditioned exclusively or almost exclusively on the presence of the rare gases. This is obtained by arranging the alkali metal cathode, which naturally ejects particles or vapors out of the glowing basis of the light arc, in such a manner that the particles or vapors do not reach the light tube proper but are held back and returned so that they do not at all, or practically not at all, exist in the illuminating part of the tube. From this result twofold advantages: (1) The rare gases are caused to illuminate under the described conditions with a very small potential loss of the current used and (2) The alkali metal cannot blacken the light tube by condensation and much less cannot reduce-the elements of the light tube (glass, silica, quartz) and by reason thereof make said tube opaque.

It is to be further said that the use of the alkali electrode guarantees the presence of rare gas free from ordinary gases, even when some small leaks would permit the entrance of air.

The electrodes .may consist of metal or alloys either fluid or solid at room temperature. Solid alkali metals, as for example sodium or lithium, generally possess higher vaporizing points whereby, naturally, the passing of the metal particles or vapors into the illuminating tube, in which there is to be only rare gas, is much more easily dcferred than when one uses metal which melts at a lower temperature, but which at the same time evaporates more easily, as, for instance, potassium. metals usually pass into fluid condition after the current has been flowing for some time, yet the melting and solidifying in connecting and disconnecting does not entail any danger to the tube since these metals, even in a solid condition, retain sufficient softness not to burst the tube.

In the drawings various modified forms of lamps according to the invention are represented.

In the drawings Figures 1 and 2 show a lamp in which the holding back or return of the vapor is assisted, without hindrance .to the passage of the current, by means of a grating placed within the electrode receptacle a and consisting of a number of very wide meshed wire nets a laid over one another and arranged over the electrode 6. The wire nets 0 may be made of any material for instance of quartz or porcelain. Figs. 3 and 4 show an electrode receptacle a in which the space over the alkali electrode Z) is subdivided for the same purpose by means of a grill work a! such as, for exam ple, quartz plates. The latter may be fixed in place in any convenient manner. The best way of making the grill work is by putting together quartz plates provided with cuts of a width corresponding with the thickness of the plates and a length equal to half the breadth of the plates. Figs. 5 and 6 illustrate an electrode receptacle a with cooling ribs 6 on its outer wall. These ribs can be made of iron, copper nickel, brass etc. They are fixed on a metal ring and the latter is slipped over the receptacle 6 and held in place by any convenient means. Fig. 7 shows an electrode receptacle 0; with cup-like insert 7. In Fig. 8 there is shown an electrode receptacle a which forms a separate part. i

In order to more efliciently prevent the entrance of alkali metal vapor into the light tube the electrode receptacle is therefore pro vided with a correspondingly large cooling surface, 2'. e., the several means indicated in Figs. 1 to 6 or other equivalent means may be used.

It is preferable to use, instead of pure rare It is true that these gases, mixtures thereof, such as, for example, a neon-helium mixture, since they frequently make possible a greater voltage fall per unit of length of the light tube. These mixtures increase the richness of the spectrum lines.

Since, in contradistinction from mercury lamps, the light point on the cathode fixes itself most readily at the walls of the receptacle and, if the latter consists of glass, causes it to burst, the use of quartz receptacles is especially to be advised. However, even with the use of glass receptacles, the purpose of the invention may be obtained, if one, by means of known inserts, consisting, for instance, of quartz, as'indicated on Fig. 7, prevents the moving of the light point to the glass Wall. For inserts according to Fig. 7 materials are especially to be recommended with which evaporated and recondensed metal does not react chemically in a marked degree, and to which such metal does not adhere, so that the running together in drops is made possible, for instance, quartz, magnesia, porcelain or thorium oxid may be thus used. The electrode receptacle may also constitute a part separate from thatof the light tube and be hermetically connected with the light tube, for instance by means of a suitable cement (Fig; 8). In this case the receptacle may also be made of metal but insert as shown in Fig. 7 should then be used. The lighting of the lamp, according to the invention, takes place in known fashion either by means of high tension impulses or by means of coitact lighting by the aid of magnetically moved auxiliary anodes of rigid material.

The alkali metal or alkali alloy employed as a cathode may have other metals added to it or mixed with it. Since the alkali metal is not only useful as a cathode but also as an anode, it is generally preferred to make the anode of alkali metal also, for the reason, among others, metals which readily thereby avoided.

Where, in the claims which follow, I have used the word vapors I mean it to signify not only a gas in the narrow sense of the word but also such small particles as may be spurted or otherwise given oil from the cathode.

I claim: 1. In an electrical gas lamp adapted to be that foreign give off gases, are

operated by are like discharges, a cathode 6f electro-positive metal, alight tube containing a rare gas capable of acting as a conductor. adjacent to said cathode, and means for preventing vapors of said metal from entering said light tube.

2. In an electrical gas lamp adapted to be operated by are like discharges, a cathode of electro-positive metal, a light tube containing a rare gas capable of acting as-a'con-- ductor adjacent to said cathode, and means for arresting the vapors of said metal near to the cathode so as to prevent them from entering said light tube.

3'. In an electrical gas lamp adapted to be operated by arc like discharges, a cathode of electro-positive metal, a light tube containing a rare gas capable of acting as a conductor adjacent to said cathode, and obstructing means between the cathode and the light tube for preventing cathode vapors from entering said tube.

4:. In an electrical gas lamp adapted to be operated by are like discharges, a cathode of electro-positive metaha light tube containing a rare gas capable of acting as a conductor adjacent to said cathode, and means comprising material to which the cathode material is non-adherent between said cathode and the light tube.

5. In an electrical gas lamp adapted to be adjacent to the cathode for preventing cathode material from entering said light tube.

In testimony whereof I have hereunto set my hand in the presence of two. subscribing witnesses.

Witnesses HENRY HA WOLDEMAR srnn,

Ham.

FRANZ SKAUPY. 

